Film wrapping machines for wrapping products or articles in wrapping film conventionally comprise a film roll upon which a supply of the wrapping film is disposed, and a plurality of rollers around which the wrapping film is routed so as to have a predetermined amount of tension developed within the film such that the wrapping film exhibits a predetermined or requisite amount of tension required for the film wrapping operation. One conventional type of film wrapping machine comprises a set of rollers fixedly mounted within respective upper and lower frame members whereby, for example, a leading end of the wrapping film must be withdrawn from the film supply roll and manually routed or threaded through and around the set of tension rollers. This process or operation, however, has proven to be very awkward, difficult, and tedious for operator personnel because the film must be threaded or routed beneath the upper frame member and between the tension rollers. Such requirements have additionally manifested themselves in rendering the wrapping film threading or routing process or operation quite time consuming whereby non-productive downtime, attendant for example the exchange of wrapping film supply rolls when a particular wrapping film supply roll which has been depleted is being removed and a new wrapping film supply roll which has a fresh supply of wrapping film thereon is being installed, has been relatively extensive.
In order to improve upon the foregoing conventional type of film wrapping system such that the film threading or routing operation is rendered less awkward, difficult, tedious, and time-consuming, another conventional type of film wrapping system was developed wherein the threading or routing of the wrapping film around the various tension rollers was, in effect, rendered "automatic" due to the presence or relative disposition of, for example, a plurality of fixed film tension rolls and a plurality of relatively movable press rolls. A system of this type is disclosed, for example, within U.S. Pat. No. 4,914,891 which issued to Suolahti on Apr. 10, 1990.
With reference being made to FIG. 1 of the present patent application drawings, which corresponds to FIG. 2 of the drawings of U.S. Pat. No. 4,914,891, the patented system of Suolahti is seen to comprise a pair of vertically oriented film tension rolls 23 which have their upper and lower ends respectively mounted within fixed upper and lower frame plates 22 and 21. A drive motor 27 and transmission means 28 are mounted upon the upper frame plate 22 and are operatively associated with the tension rolls 23. In a similar manner, three vertically oriented press rolls 30 are mounted upon a frame 29 which is pivotally mounted with respect to the frame plates 21 and 22, and the tension rolls 23 thereon, such that the frame 29, and the press rolls 30 thereof, is pivotally movable, as indicated by the arrow, between a closed position, at which the three press rolls 30 are disposed in an interdigitated manner upon opposite sides of, and between, the two tension rolls 23 whereby wrapping film from a wrapping film roll 5 may be properly routed, threaded, or disposed around the tension rolls 23, and an opened position, as illustrated, whereby a depleted wrapping film roll 5 may be removed from the framework comprising upper and lower frame plates 22 and 211, and a new wrapping film roll 5 may be installed in place of the previously depleted wrapping film roll 5. The lower fixed frame plate 21 is provided with a slot 33 within which a bushing 34 of wrapping film roll 5 is accommodated. When the new wrapping film roll 5 is installed within the framework and between the upper and lower frame plates 22 and 21, the film is withdrawn from the film roll 5 and moved across the tension rolls 23 in a direction transverse to the vertically oriented axes of the tension rolls 23.
Another system similar to that of Suolahti is disclosed within U.S. Pat. No. 5,414,979 which issued to Moore et al. on May 16, 1995. This patented system is likewise seen to comprise, as illustrated in FIG. 2 of the present patent application drawings which corresponds to FIG. 1 of the drawings of the noted patent to Moore et al., a first dispenser frame assembly 26 upon which is mounted a pair of vertically oriented upstream and downstream prestretch rollers 36 and 40, an orienting roller 80, and a spindle 30 for supporting a roll 32 of stretch wrap packaging material 14. The system further comprises a second dispenser frame assembly 50 upon which an intermediate orienting roller 52, and orienting rollers 82 and 84, are mounted for cooperating with the prestretch rollers 36 and 40, and the orienting roller 80, of the first dispenser frame assembly 26 in an interdigitated manner as illustrated. The second dispenser frame assembly 50 is pivotally mounted relative to the first dispenser frame assembly 26 by means of a hinge mechanism 56 such that, for example, the second dispenser frame assembly 50 can be moved between opened and closed positions relative to the first dispenser frame assembly 26 in connection with the threading or routing of the packaging material 14 from the supply roll 32 when a new supply roll 32 of film or packaging material 14 is installed and wherein the film or packaging material 14 is to be properly tensioned. As was the case with the patented system of Suolahti, the film or packaging material 14 is withdrawn from supply roll 32 and moved across prestretch rollers 36 and 40, and orienting roller 80, in a direction transverse to the respective vertically oriented axes of the rollers 36, 40, and 80.
While it may therefore be appreciated that the systems of Suolahti and Moore et al. comprise improvements over the prior systems, wherein manual threading or routing of the packaging or wrapping film between and around the various tension or prestretch rollers and the press or orienting rollers was required, in that the threading or routing of the packaging or wrapping film was rendered substantially easier in view of the opening of the roller system by means of the movement of the press rollers or the orienting rollers away from the tension rollers or prestretch rollers, such systems of Moore et al. and Suolahti nevertheless present operational problems or drawbacks in view of the fact that attendant a supply film replacement or replenishment operation, the movable frame assemblies must be operated between their opened and closed positions in order to permit the new supply of wrapping or packaging film to be inserted, routed, or threaded between the various rollers. Such movements of the movable frame dispenser or assembly are therefore still time-consuming in view of the necessary opening and closing operations, and in addition, such operations still result in non-productive downtime.
A need therefore exists in the art for a new and improved film packaging or wrapping machine stretch head, station, or dispenser wherein the routing or threading of the film or packaging material is facilitated in a readily quick and simple manner, and wherein further, in the interest of production economy, the moving components of such prior art stretch head, station, or dispenser are able to be eliminated.